Zero Waste Scotland has developed a tool, covering new environmental indicators, that offers additional insights into the overall environmental cost of waste and materials. The organisation’s Dr Ramy Salemdeeb, and Ruth Saint, of Edinburgh Napier University, explain.
Weight-based targets are the bedrock of numerous policies instrumental to the evolution of the waste sector. Since 2011, the amount of waste generated in Scotland has decreased by 4.4 per cent, with nearly 11 per cent more waste being diverted from landfill, which has led to a 7.5 per cent increase in recycling, reaching 60.7 per cent in 2018.
The waste sector has, undoubtedly, benefited from the adoption of weight-based targets. Nevertheless, as the number of countries declaring a climate emergency increases, there is growing interest in moving from weight-based to impact-based targets, and contributing to combating climate change. We need to support the evolution of the sector while considering environmental threats and climate change.
Carbon-intensive materials, such as textiles and plastic wastes, make up a small percentage of Scotland’s waste by weight, but represent a large proportion of its whole life-cycle carbon impacts. Similarly, food waste accounts for five per cent of waste by weight, but 22 per cent of all waste carbon impacts.
Carbon-intensive materials, such as textiles and plastic wastes, make up a small percentage of Scotland’s waste by weight, but represent a large proportion of its whole life-cycle carbon impacts. Similarly, food waste accounts for five per cent of waste by weight, but 22 per cent of all waste carbon impacts.
Defra’s waste strategy for England advocates a shift to impact-based accounting, while other organisations – including the Environmental Services Association, the International Solid Waste Association and EU ACR+ – have launched a campaign to support their members to reduce the emissions linked with local resource management by 25 per cent by 2025.
The current focus of impact-based accounting is on the carbon footprint of waste. Scotland is a pioneer in this, with the release of the groundbreaking Scottish Carbon Metric (SCM) 2011, which was developed by Zero Waste Scotland to give an insight into the environmental impacts of waste. In 2017, the SCM was integrated into Scotland’s official reporting on household waste data statistics for the first time.
Embracing impact-based accounting
The SCM has helped us to realise the significance of carbon impacts associated with the production of material, known as embodied carbon. In 2015, Zero Waste Scotland published a report showing these embodied impacts are responsible for more than two-thirds of the whole life-cycle carbon impacts of Scotland’s waste.
Food waste and textiles are just two examples, highlighting the importance of considering waste from a whole life-cycle perspective, not only through waste-management activities. Producing food waste emits six times its own weight in carbon emissions; textiles create 22 times their weight. Including these embodied emissions draws attention to the significant impacts of producing materials in the first place – when a product is thrown away, it is not only the product itself that is wasted, but all the energy and impacts associated with its production and use up to that point.
The second lesson we learned from using the SCM is the importance of going beyond carbon. As countries ramp up their efforts to reach net-zero targets and achieve a green Covid-19 recovery, we believe whole life-cycle impact assessment should be expanded to consider the overall environmental cost of waste generation. We cannot focus solely on carbon reduction or we risk shifting the problem to other potential areas of damage, such as land-use change or water and resource depletion. There is a need to go beyond carbon and quantify other key environmental indicators, to ensure damage is not simply becoming a burden elsewhere.
Realising the importance of adding new environmental indicators, Zero Waste Scotland has developed a tool that covers new environmental indicators. Designed in partnership with Edinburgh Napier University and Cambridge Architectural Research, the tool will give decision-makers additional insights into the overall environmental cost of waste and materials.
Figure 1 gives an example of the insights it can potentially offer. The charts illustrate the environmental impacts of three packaging materials – aluminium, PET plastic and bio-plastic – with focus on five environmental indicators: carbon impact, air quality, land use, and water and material depletion.
Our analysis suggests that bioplastics, when compared to fossil-based plastics, have lower carbon impacts but are associated with a substantially higher burden on land and water sources. Aluminium is associated with the highest carbon, air quality and material depletion impacts, but has the lowest burden on water sources. This analysis is based on virgin materials and does not account for aluminium being a widely recycled material that can be recycled infinitely. In the US, for example, cans have, on average, 68 per cent recycled content, compared with just three per cent for plastic.
What’s next?
One of the key strategic outcomes of Zero Waste Scotland’s corporate plan is responsible consumption, where we can have the greatest impact in tackling climate change and reduce our demand for raw materials and energy.
Looking beyond carbon is deemed to be essential in any post-Covid recovery plans, as it provides invaluable insights into the true environmental cost of materials and waste.
Zero Waste Scotland recently commissioned a review study of indicators that go beyond carbon to determine areas that will help us understand the overall environmental impacts of waste and materials and, consequently, act more in line with our strategic goals. Once the tool is completed, 2019 waste data will be analysed, with an output expected in 2021.
